Automatic drawoff and automatic tensioning device for full-fashioned knitting machines



Nov. 3, 1942. A. HOFMANN arm. 2,300,830

AUTOMATIC DRAW-OFF AND AUTOMATIC TENSIONING DEVICE FOR FULL-FASHIONEDKNITTING MACHINES Filed March 23, 1940 4 Sheets-Sheet l Nov. 3, 1942. A.HOFMANN ETAL 2,300,830

AUTOMATIC DRAW-OFF AND AUTOMATIC TENSIONING DEVICE FOR FULL-FASHIONEDKNITTING MACHINES Filed March 23, 1940 4 Sheets-Sheet 2 Jul/anions E:elk M7672 3531M 75mins! 3, 1942- A. HOFMANN E'IAL 2,300,830

AUTOMATIC DRAW-OFF AND AUTQMATIC TENSIONING DEVICE FOR FULL-FASHIONEDKNITTING MACHINES Filed March 2:5, 1940 4 Shee'ts-Sheet a 170 1&4

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Nov. 3, 1942. HOFMANN r 2,300,830

AUTOMATIC DRAW-OFF AND AUTOMATIC TENSIONING DEVICE FOR FULL-FASHIONEDKNITTING MACHINES Filed March 23, 1940' 4 Sheets-Sheet 4 Jonah! G.Tratnef' .Attorn Q5].

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Patented New 3, 1942 i I v UNITED STATES PATENT OFFICE.

.AU'roMA'nc DRAWOFF AND AUTOMATIC.

TENSIONING DEVICE FOR FULL-FASH- IONED KNITTING MACHINES Alfred Hofmann,Palisade, and Donald G. Trutner, North Arlington, N. J., assignorstoAlfred Hofmann, Inc., West New York, N. J.

Application March 23, 1940, Serial No. 325,562

23 Claims. (01. 66-149) The present invention relates to fiat knittingthat heretofore utilized in the art, whereby the machines and, moreparticularly, to automatic tension no longer depends upon a force, thepower draw-off and automatic tensionlng of fabric being of which in turndepends upon the inertia of knitted on full-fashioned knitting machines.weights or inherent strength of springs, and can It is a recognized factin the art of knitting be changed only to the extent that the additionfiat fabric, especially full-fashioned hosiery or removal of weights orsprings would provide, fabric, that such fabric and particularly thelast but upon a force, the power of which is created knitted course ofloops must be drawn away from by controllable, adjustable, positivelydriven the needles as soon as said loops are cast off the means, and canbe varied by the controlled, adneedles. For that purpose, commonly knownjusted action of such means whereby the tension knitting machines areequipped with a so-called imparted to the fabric may be regulated to thedraw-off or take-up motion, which maintains the very degree necessary toproduce the best results fabric under tension and thus acts to clear theobtainable.

cast off knitted courses from the needles as they' It is alsowell knownin the art of knitting fullrise to the required position for theformation fashioned stocking fabrics that the fabric tension of thesucceeding courses. must be altered as knitting progresses, in order Theconstruction generally used includes a to knit loops of uniform sizethroughout the rotary shaft carrying so-called' ware rollers, length ofthe stocking. Since full-fashioned which correspond in number to thenumber 6f stocking fabrics are narrowed during knitting, knittingsections in the machine and to which the fabric tension must be reducedas the length the fabric blanks or webs are connected by suitof thefabric increases. Otherwise, loops of variable attaching means, saidrotary shaft being one sizes would be produced. operated by weights orexpansion springs exert- Heretofore, the increasing or decreasing. ofing a pull on the shaft in a predetermined ditension to which the-fabricis subjected has been rection to rotate said shaft for drawing thefabric obtained by the manual or mechanical addition blanks or webs awayfrom the needles. or removal of weights or springs acting on the Thisdrawing of the fabric away from the ware roller shaft. The manualaddition or reneedles is of the greatest importance because the moval ofweights or springs, of course, requires production of even, regularappearing courses is strict attention on the part of the operator,largely dependent upon it. Too much tension whereas the mechanical meansso far devised for not only misaligns the needles laterally, particutheaddition or removal of weights or springs are larly near .the selvedges,and so causes broken too complicated and cumbersome to be of pracneedlesand imperfect fabric, but also misaligns tical value. the needles in thedirection of the tension, there- Consequently, it is an important objectof the by varying the position of the hooks of the invention to providesimple, yet effective, mechaneedles as they draw the kinked yam-01f thenism which may be readily associated with the sinkernibs so that loopsof different sizes will knitting machine to function concurrentlytherebe produced, whereas not enough tension will with at certaindefinite points in the course of result in the failure of the fabric tobe drawn its knitting operation for effecting automatically withsufiicient rapidity to clear the needles in a controlled tension of thefabric during its protheir movement for the formation of thesucceedduction, ing courses. One of the most serious problems incidentalto With the use of weights or springs exerting a, the proper tensioningof full-fashioned stocking pull on the ware roller shaft, to rotate thesame fabrics arises from the necessity of narrowing the V for tensioningthe fabric, it is impossible from a fabric. Since, during narrowing,only a relapractical standpoint, to regulate the fabric tentively smallnumber of edge loops of the fabric sion with positive certainty to therequired nicety are lifted ofl the knitting needles by comparabecausethe tension imparted to the fabric detively delicate transfer points,the remaining pends directly upon the number and particular loops of thefabric being left on said needles, and size of the weights, or thenumber and inherent since these points cannot, without detrimentalstrength of the springs used. springing, carry the weight of the normalknit- It is, therefore, the primary purpose of the inting fabric take-uptension on said loops, it is vention to provide a fabric draw-off andtake-up necessary to provide a so-called fabric tension method anddevice conducted and constructed release motion. according to aprinciple basically different from 5 The present invention, therefore,contemplates the provision of improved means capable of effecting arelease of the fabric tension during each narrowing operation bymomentarily reducing the tensioning force from its adjusted full degreenecessary for knitting only to that extent required for narrowing, thuspreserving a predetermined degree of tensioning force on the fabric sothat the loops remain in proper engagement with the needles and transferpoints during narrowing, said improved means being further capableimmediately upon termination of narrowing to reinstate automatically thefull adjusted tensioning force existing before the release.

In certain existing machines of the type to which this inventionpertains, there is provided specially devised mechanisms whereby thefabric may follow the horizontal movement of the needles during the loopforming operation for the purpose of preventing undue stretching ofloops as the needles are moved against the presser edge and ofeliminating other excess pull on the fabric when the loops are held bythe knockover bits during knitting which results in even, uniform loopsshowing no sign of stretch and providing uniform fabric texture.

The present invention makes provision for obtaining such advantageousresults, but this is without the necessity of additional speciallydevised mechanisms.

Moreover, the invention is particularly distinguished by the provisionof an automatic tension and take-up mechanism incorporating a compoundrotating and sliding tension applying and regulating device which ischaracterized by its inherent freedom from fricticn, thereby overcomingfriction detrimental to accurate control and simplifying theconstruction and operation of said mechanism. e

Other important objects and advantages of the invention will be in partobvious and in part 40 pointed out hereinafter.

In order that the invention and its mode of operation may be readilyunderstood by those skilled in the art, we have, in the accompanyingdrawings and in the detailed thereupon, set out a possible embodiment ofthe invention.

In these drawings:

Figure l is a sectional view through a flat knitting machine,illustrating in elevation the improved automatic take-up and tensioningdevice applied thereto;

Figure 2 is a top plan on an enlarged scale of a portion of themechanism shown in Figure 1;

Figure 3 is an end view of the same;

Figure 4 is a detail in elevation of the releasing plate Figure 5 is asection taken on line 5-5 of Figure 4;

Figure 6 is a detail of a portion of the regulating 6o mechanism;

Figure 7 is a detail illustrating a modification thereof;

Figure 8 is a side elevation, with parts in section, of the automatictake-up and tensioning mechanism;

Figures 9 to 13 inclusive are views similar to Figure 8, illustratingthe various positions of the mechanism in the successive stages of itsoperation;

Figure 14 is a side elevation of a modification of the fabric take-upand tensioning mechanism.

Referring more particularly to the drawings, wherein like characters ofreference will designate corresponding parts throughout, the ma- 5rockable needle bar shaft 30 shaft 24.

35 ends attached to the lever 60,

late, thereby moving the needle bar chine frame is designated at 20, andcarries the usual bearings for supporting the various shafts of theknitting machine including the rotatable longitudinally shlftable maincam shaft 22, the 24, and the rotatable ware roller shaft 26. Themachine frame is also provided with the usual center bed 28, back beam30, front beam 32, and front table 34.

Arranged about the center bed 28 in the cus- 1o tomary manner are themultiple knitting sections,

one of which is designated in its entirety for convenience herein by thereference character 38. The knitting section 36 comprises the straightneedle bar 38 with its bank of needles 40 disposed to cooperate with'thepresser edge 42, sinkers and dividers 44, and knockover bits 46 for theformation of the courses of loops in the fabric being knitted on themachine.

Yarn is fed to the needles by means of the yarn carriers 48 connected tothe carrier bars 58 supported in the brackets 52 on the machine frame Asis customary in the straight needle bar type of knitting machine, theneedle bar 38 is capable of both vertical and horizontal movements. For

the purpose of imparting to the needle bar its vertical movement, saidneedle bar is provided with extension arms 54 pivoted, as 'at 56, to alink 58 in rigid engagement with the needle bar A lever 60, also rigidwith the needle bar shaft 24, carries a roller 62 adapted for ridingengagement with a cam 64. Constant contact of the roller 62 with theassociated cam 64 is assured by means of a spring 66 having one of itsand the other of its ends suitably attached to the back beam of themachine frame.

From the foregoing, it will be understood that whenever the roller 62contacts the cam 64, the same will cause the needle bar shaft 24 tooscil- 38 up and down for its knitting motion during a revolution of themain cam shaft 22 in the course of its knitting cycle. The needle bar 30receives its description basedhorizontal movement through the well knownmechanism not shown herein.

The control of the functions of the knitting machine incidental to itsoperation is governed,

as usual, by the pattern chain mechanism 68, the construction and actionof which are well known in the art and, therefore, require no elaboratedetailed description herein.

In order to withdraw the fabric, under tension, away from the needles4!! as the fabric is knitted,

there is suitably supported upon the machine frame the rotatable shaft26 which may be the usual ware roller shaft extending through the lengthof the machine and carrying ware rollers 10 to which are attached'bymeans of straps 12 (or like connecting means) the fabric blanks, such asthe stocking blank represented at S. Rotation of the shaft 26 in thedirection of arrow A, of course, will draw the fabric blank in thedirection of arrow B and thus maintain said fabric blank under tension.

For that purpose, and in accordance with the present invention, themachine is provided with an improved automatic draw-off and automatictensioning mechanism 80, several possible em- 70 bodiments of which willnow be described.

Disposed at a convenient point along the length of the ware roller shaft26 to extend transversely thereof is a bracket frame 82 which, in theembodiment more clearly shown in Figures 1, 2, and

8, includes an end portion 86 adapted to receive the rotatable wareroller shaft 26. The bracket frame 84 is moreover formed with a pair ofaligned bearings 88 and 80 positioned to support a stub shaft 82 forfree rotatable and longitudinally slidabie movements. As shown in thedrawings, one bearing 88 is located on one side of the ware roller shaft26, whereas the remaining bearing 80 is located on the other side ofsaid ware roller shaft so that the portion of the stub shaft 82extending between said bearings becomes located in a position transverseto the ware roller shaft 26.

Fixed by means of lock screws 84 (or the like) to said portion of thestub shaft extending between the bearings 88 and 80 of the bracket 82 isa worm 86 of a length relatively shorter than the length of the stubshaft portion extending between said bearings. Suitablewashers (or thelike) such as represented at 88 and I may be placed on the stub shaft 82so as to lay between the ends I02 and I04 of the worm and opposedbearings 88 and 80 respectively.

Preferably interposed between the washer 88 and end I02 of the worm 88is a compression spring I08 normally acting to urge the stub shaft 82and worm- 86 connected thereto in an outward direction, that is, in thedirection of the arrow C. Of course, it is to be understood the springI08 may be placed at any point along the length of the stub shaft 82where said spring will act normally to urge the shaft, together with theworm, in said direction 0-.

Enmeshed with the worm 88 is a worm wheel I08 affixed to the ware rollershaft 28 so that movement of the worm will actuate said shaft throughthe worm wheel in the manner hereinafter described in detail. It is tobe noted that the threads of the worm and teeth of the worm wheel are sorelated that rotation of the stub shaft 82 in the direction of arrow Dwill rotate the ware roller in its take-up direction A. The stub shaft82 may be rotated in the direction D by means of a hand wheel IIOsecured to the end portion of the stub shaft 82. This shaft 82 is alsoadapted to be rotated in direction D automatically during the operationof the knitting machine. For that purpose, there is provided a ratchetdevice II2 which, in the embodiment shown, comprises a ratchet wheel II4 fixed onto the shaft 82 and a pawl I I8 carried by a bracket H8freely received on said shaft 82, but held thereon in spaced relation tothe ratchet wheel H4.

The pawl carrying bracket I I8 is connected by means of a link I20 to anarm I22 secured to the needle bar shaft 24 so that, upon oscillatingmovement of the latter in the manner hereinbefore stated, the arm I22will be swung thus operating the ratchet actuating pawl II8.

It is to be noted that the worm 88 has a relatively small diameter, andthat the helix angle of the worm thread is relatively steep(approximately 27). It is also to be noted, particularly from Figure 3,that the worm wheel I08 is relatively wide and that the formation of theteeth is such as to conform to the steep helix angle of the worm thread.Because of this relationship of the worm 88 and worm wheel I00,-there isproduced a drive which is not self-locking, but one which is capable ofrotation in either direction whether the turning force is applied to theworm 88 or to the worm wheel I08. Thus, referring for instance to Figure1, when the spring I08 under compression tends to thrust the shaft 82 tothe left, or when a turning force is applied to the worm wheel I08 torotate the same in a direction opposite to that indicated by arrow A,such as occasioned by a tension force created within the fabric Sanchored on the needles 40, then said thrust of turning force tends torotate the worm 88 and its shaft 82 in a direction reverse to thatindicated by the arrow D and, therefore. the ratchet device II2associated with the shaft 82 in the manner above stated will follow thereversed rotation of said shaft 82.

The ratchet wheel H4 and stub shaft 82 are normally prevented from backrotation by means of a dog I24 pivoted as at I28 to an extension I28 ofthe bracket frame 82 and disposed to engage said ratchet wheel. The dogI24 may be urged into it engagement with the ratchet wheel II4 by meansof a spring I having one of its ends attached to said dog and the otherof its ends suitably connected to the bracket frame 82.

cooperatively associated with the dog I24 to control the functionthereof is a regulating mechanism I82 which may be set and actuatedautomatically during the operation of the knitting machine, or may beset manually at the start of the knitting machine and then manuallyreset as the knitting progresses.

In Figures 1, 3, and 6, there is shown a possible construction for theautomatically set and operated regulating mechanism. In thisconstruction, there is provided a knob I34 having a stepped surface I88and formed with a toothed portion I38. The knob I84 is mounted forrotation on a stud I40 on the extension I28 of the bracket frame 82 andis disposed to contact the free end I42 of the dog I24. Rotation isimparted to the knob I84 by means of a pawl I44 engaging the toothedportion I88 of said knob and carried by one end portion I48 of a rodI48, having its other end portion I50 extended through a guide I52 andprojected inclose proximity to the pattern chain 88 of the knittingmachine. A set of buttons I54 is arranged on said pattern chain and isadapted, with actuation of the latter, to be brought in contact with theend portion I50 of the rod I48, thus moving said rod in the direction ofarrow E, accordingly causing the pawl I44 to impart a partial rotationto the knob I84, thereby bringing the different steps on its steppedsurface I88 in successive registration with the free end I42 of the dogI24 and therefore locating the ratchet engaging end of said dog invarious positions as the operation of the knitting machine progresses.

In Figure 7, there is shown a possible construction of the manually setand reset regulating mechanism. In this construction, a knob I58 havinga flat surface I58 and formed with a knurled portion I80 is mounted inscrew-threaded engagement with a stud I82 carried by said extension I28of the bracket frame 82, and is disposed to contact the free end I42 ofthe dog I24. Thus by screwing the knob I56 in and out, the fiat surfaceI58 thereof is brought nearer to and further away from its support, andbeing in engagement with said free end I42 of the dog I24, locates theratchet wheel engaging end of said dog in various positions.

Disposed concentrically with the ratchet wheel I I4 and mounted foroscillation on the stub shaft 82 is a plate I84 preferably having theshape more clearly shown in Figure 4. This plate has a sector cut-awayto constitute a forward edge I88 which is beveled for engagement withthe ratchet wheel engaging end of the pawl H8. The plate also has anaperture I88 cut transversely thereof for the passage of the ratchetwheel engaging end of the dog one side of the plate at said end of saidaperture I68 having a beveled edge I10 adapted for engagement with saidend of the dog I24. The plate may be moved to bring the beveled edgesI66 and I10 thereof in engagement with the pawl H6 and dog I24 manuallyor automatically. For that purpose, the plate I64 may be formed with anextension I12 terminating onto a finger I14. Thus by manually raisingthe finger I14, the plate moves in the direction of arrow F. A rod I 16may also be provided with one end portion I18 suitably connected to theplate extension and its other end portion I80 passing through guide I52and extending in close proximity to the pattern chain 68. A set ofbuttons I82 is arranged on said pattern chain to be brought, withactuation thereof, into contact with extended end portion I80 of saidrod I16, which is thus raised to move the plate I64 automatically in thedirection of arrow F.

In Figure 14, there is shown a modified construction of the automaticdraw-off and tensioning mechanism which is particularly devised for usewhenever it is desired to provide such a mechanism adapted to releasethe tension in an automatic fashion during the narrowing of the fabricbeing knitted on the knitting machine. This modified construction isbasically similar to the preferred embodiment hereinbefore described,with the exception that there is provided a bracket frame 82a mountedfor sliding movement to a bearing block 200 conveniently carried by theware roller shaft 26. The bracket I24 therethrough,

.frame 82a is formed with an extension 202 connected, as at 204, to onearm 206 of a bell crank lever which is pivoted on a supporting shaft208. The remaining arm 2i of the bell crank lever carries a roller 2I2adapted, to be urged into riding engagement by means of a spring 2 witheither a neutral cam 2I6 or an active cam 2I8 on the main cam shaft 22,depending upon the position of the latter.

The cams 2I6 and 2| 8 are so arranged on the main cam shaft 22 that whensaid shaft is in normal knitting position, the neutral cam 2I6 is inengagement with the roller 2I2, thus maintaining the bracket frame 82arigid in relation to the tension spring I06 and associated elements, butwhen said shaft is shogged to its narrowing position, the active cam 2I8is in engagement with said roller 2I2, ing movement of the bracket frame82a in the direction of arrow G, thereby relieving the worm wheel I08 ofthe tension of the spring I06.

The tension and take-up operation of the device will be understood moreclearly upon reference to Figures 9 to 13 inclusive. In the positionillustrated in Figure 9, it is assumed that the welt of the stockingfabric has just been turned, which has necessitated the release of thetension so that the fabric S is slacked. At this point, it may be statedthat while the slack in the fabric S may be taken up automatically, bysetting the machine in operation, it is preferable to take up the slackinitially by manual rotation of the shaft 92 by means of the hand wheelIIO before the machine is actually set in operation. In this manner,knitting of additional courses takes place only after the fabric S isunder sufficient tension to assure the proper formation of loops in suchadditional courses.

The turning of the shaft 92, of course, rotates the worm gear 96 whichdrives the worm wheel accordingly causing the slidthus taking up thefabric 8, as represented in Figure 10, until the tension of the fabricreaches its maximum, when further rotation of the worm wheel in thedirection of arrow A will be prevented because of the force opposedthereto by the fabric which is in engagement with the fixed needles 40.Under these conditions, it will be appreciated that any turning of theshaft 92 in the direction of arrow D will cause the worm travel inrelation wheel I08, thereby sliding the shaft 92 inwardly, that is, inthe direction of arrow H and, accordingly, as indicated in Figure 11,compressing the spring I06, thus storing a force therein.

stored in the spring is controlled by the regulating mechanism I22, mayhave any one of the possible construct tions hereinbefore described, andthe operation will be fully explained hereinafter. The spring I06, beingcompressed as above stated, it will be appreciated that upon theknitting of additional courses onto the fabric which thereby loses itsoriginal tension, said spring becomes free to expand and thus, asrepresented since the shaft and worm gear, being locked by thecooperative function of the pawl H8 and dog I 24, are prevented fromrotation. The worm gear then acts as a rack and imparts a rotation tothe worm wheel I08 and ware roller shaft 26 in the direction of arrow A,consequently taking up the added length of the fabric occasioned by theknitting of additional courses thereonto, and thus maintaining thefabric in its original tension.

With the operation of the knitting machine through its subsequentknitting cycle, the cam 64 and main cam shaft 22 (Figure 1) actuate theratchet mechanism II2 so that, as represented in Figure 13, the pawl II6rotates the stub shaft 92 and worm gear 96 in the direction of arrow D,again compressing the spring I06 by causing the shaft to move in thedirection of arrow H due to the riding of said worm gear tation becauseof the force opposed to such rotation by the fabric under tension.

The operation of the device, as described, to automatically take up andtension the fabric as additional courses are knitted is repeatedthroughout the entire knitting of the stocking blank.

Attention is particularly called to the fact that, in the use of thedevice, the action of the predeterminable compression force of thespring I 06 against the worm 96 rotatively transmitting this force tothe take-up shaft 26 by means of the worm wheel I08, as well as therefeeding of the lost force to said spring, take place consecutively butin a manner that the active tensioning I force of the spring remains ina predetermined I08 and ware roller shaft 26 connected thereto,

(and, for all practical purposes, in a constant) relation to thecombined tension exerted by the plurality of fabric blanks undertension. Furthermore, it is pointed out that the desired tension isobtained by compressing the spring until its reaction is equal to thetension desired, and that this tension is not exceeded because of theposition of the dog I24.

As known in the art, it is desirable to reduce the tension as thestocking fabric reaches certain predetermined lengths and, in accordanceto the stationarily with the present invention, this maybe accomplishedautomatically by actuation of the regulating mechanism I32 as shown, forinstance, in Figure 1 of the drawings. The operation of this type ofmechanism is as follows:

As the knitting machine functions, the pattern chain 68 is actuated ascustomary so that a button I54 eventually reaches a position to registerwith the end I50 of the rcd I48 to raise the same in the direction ofarrow E and, accordingly, rotate the knob I34 to vary the position ofthe dog I24 in relation to the ratchet wheel H4 and thus engage thelatter at a time to control the amount of force to be stored in thespring I06. A set of buttons, such as that shown at I54, is arranged onthe pattern chain 68 so as to correspond to the points in the lengths ofthe stocking fabric where the tension thereof is to be reduced.

.With the use of the regulating mechanism shown in Figure 7, the tensionmay be varied whenever the operator finds it necessary In other words,if the operator, by feeling the fabric being knitted, determines thatthe fabric is under improper tension, the proper tension may be restoredto the fabric by manually screwing the knob I56 in or out, therebyadjusting the position of the dog I24.

By way of further explanation of the operation, function, and purpose ofthe dog I24 and its regulating mechanism I32, it is pointed out that inthe operation of the present device, the worm 86 is initially confinedaxially by the initial pressure of the spring I06. As the worm 86 isrotated by the ratchet device I I2, said worm turns the worm wheel I08together with the wareroller shaft 26 until the total tension applied toall the pieces of fabric in the several sections of the knittingmachine, reacting at the working radius of the worm wheel I08, becomesgreater than the initial pressure of the spring I06. The instant thisoccurs, the worm wheel I08 and the wareroller shaft 26 stop turning. Theworm 86, however, is still rotated intermittently by the ratchet deviceII2. As the worm wheel I08 cannot rotate, the worm 86 is transformed incharacter from a worm to a screw, with the now stationary worm wheel I08functioning as a nut. This rotation of the worm 96 will cause its bodilyadvance in a direction which will cause the spring I06 to be compressed.

As hereinbefore mentioned, the worm 86 is rigidly fixed to its shaft 92,as is also the ratchetwheel H4. The working pawl II6 mounted on itscarrying bracket H8, and the release plate I64, are confined axially onthe shaft 82 and free to rotate thereon. With this construction, theworking pawl H6 is always in the same position relative to the ratchetwheel II4, so that when the worm 86 advances rectilinearly in itsscrew-and-nut manner, the shaft 82, ratchet wheel H4, and pawl II6 movewith said worm.

Assuming that sufiicient tension has been built up in the fabric toarrest the rotation of the wareroller shaft 26 and worm wheel I08, aspreviously mentioned, and the worm 86 has moved forward against thepressure of the spring I06, these forces combine to rotate the worm 86by reason of the steep helix angle in a direction counter to that causedby the working pawl II6. Thus when the pawl II6 on its carrying bracketH8 is rotated clockwise (Figure 3), it tends to screw the worm 86forwardly. However, if there were nothing to prevent it, the ratchetwheel ll4would follow the pawl II6 back again on its return stroke. v

To overcome the natural tendency of the ratchet wheel II4 to follow thepawl II6 during the back stroke, the second pawl I24 is provided. Thispawl I24 having the fixed fulcrum I26 and the extended lower portionI42, bears against an adjustable stop surface I36 (Figure 6) or I58(Figure '7) being urged thereto by the spring I30. The position of thestop surfaces I36 or I58 definitely controls the motion of the pawl I24in a direction toward the ratchet wheel II4.

Assuming again that the tension of the fabric S has equalled thepressure of the spring I06 and the worm 96 started its movement againstthe pressure of the spring I06, for each stroke of the working pawl II6the ratchet wheel II4 will rotate a definite number of teeth, and thebacking pawl I24 will engage said ratchet wheel at the end of thestroke, effectively preventing reverse rotation of the rtachet wheel andassociated parts. This cycle is repeated for each course laid by theknitting machine until the worm 86, functioning as a screw, has movedthe shaft 82, ratchet wheel H4, and associated parts to the right, thatis, in the direction indicated by the arrow H in Figure 13, until thebacking pawl I24 is prevented by the stop surface of the regulatingmechanism I32 from following the ratchet wheel II4 further. The workingpawl II6 will continue to partially rotate the ratchet wheel II4 for'each machine cycle, but the screw action of the worm 86 will carry saidratchet wheel beyond the range of the backing pawl I24 so that theratchet wheel will follow the working pawl II6 on its return stroke.Thus there will be a constant but slight variation in tension when thisbalance is reached, but this is not sufiicient to affect the process ofknitting.

As additional courses are knitted, lengthening the pieces of fabric, thetension of the fabric will be reduced. The force exerted by the springI06 will then be greater than the fabric tension, and the worm 86 andworm wheel I08 will again change character and function as a rack andpinion. The pressure of the spring I06 will cause the worm 86 andassociated parts to move bodily to the left, that is, in the directionof arrow C in Figure 12, which will cause the worm wheel I08 to rotatecounterclockwise, taking up the newly made fabric and restoring thetension therein. This leftward movement will again bring the ratchetweel H4 in register with the backing pawl I24 which, in its cooperationwith the working pawl II6, will again screw the worm 86 against thespring I06, compressing the same to its former position.

The preceding explains how tension. control is maintained. Tensionvariation may be had simply by changing the position of the stopsurfaces of the regulating mechanism I32 which controls rightwardposition of the backing pawl I24. Obviously if the backing pawl I24 ispermitted to travel more to the right, the worm 86 in its screw-and-nutcharacter must also travel more to the right before the ratchet wheelII4 is out of the range of the pawl I24. This would mean compressing thespring I06 to a greater extent, which produces simultaneously a fabrictension increase to an equal value, because the force exerted by thespring I06 opposes the force exerted by the fabric tension. Therefore toincrease the fabric tension, the opposing spring force-is increased andthe mechanism automati -vice shown, for instance,

. 14 may be readily adapted to cally restores a balance between thefabric tension force and the spring compression force.

With that type of draw-ofl and tensioning dein Figure 8, use may be madeof the ordinary tension release mechanism found in' present-day machinesin order to temporarily release the fabric of a certain amount of itsnormal tension during the narrowing function of the knitting machine forthe formation of narrowing courses, picot courses, or the like. However,as already described in co nection with Figure 14, the draw-off andtensioning device may readily be modified to incorporate means foreffecting such-temporary release, as well as for-equalizing the tensionvariances produced by the in and out motion of the needle bar. By usingthis modified type of automatic draw-oi! and tensioning device,any'additional mechanism for releasing the tension whenever necessary ordesired may be dispensed with.

Accordingto the invention, this may be accomplished by mounting thedevice, as shown in said Figure 14. By so mounting the device, it willbe understood that whenever the main cam shaft 22 is shogged to itsnarrowing position, the cam 218 engages the roller 212, thus causing thebracket 82a to move in the direction of arrow G and, accordingly,temporarily destroy the action of the spring I06 to annihilate itstensioning force. Also, the embodiment shown in Figure provide for thetemporary release of the tension as the needles move to their inpositions, for instance, by suitably shaping the cam 2l6 or by mountingthe roller 2|! to be shifted, transversely of the arm Illl by means of ashifting fork 250 which may be controlled automatically by the patternchain or other working part of the machine in any manner well known inthe art. It is particularly to be noted in this respect that, uponreturn of the bracket 82a to its original position, the tension isautomatically restored without requiring additional adjustments. 1

Whenever it is desired to completely destroy the tension, such forinstance as to permit the turning of the welt, this may be accomplishedby manually or automatically lifting the plate I 64, in the mannerhereinbefore explained.

It is to be understood that the various embodiments of the invention asherein shown and described are capable of certain modifications and,therefore, any modifications coming within the scope of the subjoinedclaims are to be considered within the spirit of the invention.

What we claim is: 1. In a knitting machine having a rotatable draw-offware roller shaft: a worm gearing con- -sisting of a worm wheel fixed onsaid shaft and a worm enmeshed with said worm wheel; an elementinherently capable of app ying a directional force to said worm forimparting a rotating movement to the draw-off shaft through said wormwheel; and means for annihilating the directional force normally appliedto the worm by said force supplying element.

2. In a knitting machine having a rotatable draw-oil ware roller shaft:a worm gearing consisting of a worm wheel fixed on said shaft anda wormenmeshed with said worm wheel; an element inherently capable of applyinga directional force to said worm for imparting a rotating movement tothe draw-off shaft through said worm wheel; means for regulating thedirectional force to be applied to the worm by said force supplyingelement; and means for anniagainst the action of said 2,300,830 hilatingthe directional force normally applied to the worm by said forcesupplying element.

3. In a knitting machine having a rotatable draw-off ware roller shaft:a worm gearing consisting of a worm wheel fixed on said shaft and arotatable longitudinally movable worm enmeshed with said worm wheel; acompression spring operatively associated with the worm and disposed tonormally act for moving the same in one rectilinear direction forimparting a. rotating movement to the draw-off shaft through the wormwheel; means operable for rotating the worm for movement in the oppositerectilinear direction in relation to the worm wheel and against theaction of said spring to compress the same for its action on said worm;and means relieving said worm from the action of said spring.

4. In a knitting machine having a rotatable draw-oil ware roller shaft:a worm gearing consisting of a worm wheel fixed on said shaft and arotatable longitudinally movable worm enmeshed with said worm wheel; acompression spring operatively associated with the worm and disposed tonormally act for moving the same in one rectilinear direction forimparting a rotating movement to the draw-01f shaft through the wormwheel; means operable for rotating the worm for movement in the oppositerectilinear direction in relation to the worm wheel and spring tocompress the worm; means for conspring on the worm; said worm from thesame for its action on said trolling the action of said and means forrelieving action of said spring.

5. In a knitting machine having a rotatable draw-off ware roller shaftand a needle bar shaft: a worm gearing consisting of a worm wheel fixedon said shaft, and a rotatable longitudinally movable worm enmeshed withsaid worm wheel; a compression spring operatively associated with theworm and disposed to normally act for moving the same in one rectilineardirection for immovement to the draw-off shaft through the worm wheel;and means actuated by the needle bar shaft and operable for rotating theworm for movement in the opposite rectilinear direction in relation tothe worm wheel and against the action of said spring to compress thesame for its action on said worm.

6. In a knitting machine having a rotatable draw-off ware roller shaft,a needle bar shaft, and a pattern chain: aworm gearing consisting of aworm wheel fixed on said shaft, and a rotatable longitudinally movableworrn enmeshed with said worm wheel; a compression spring operativelyassociated with the worm and disposed to normally act for moving thesame in one rectilinear direction for imparting a rotating movement tothe draw-ofi' shaft through the worm wheel; means actuated by the needlebar shaft and operable for rotating the worm for movement in theopposite rectilinear direction in relation to the worm wheel and againstthe action ofsaid spring to compress the same for its action on saidworm; and means governed by the pattern chain for controlling the actionof said spring on the worm.

. 7. In a knitting machine having a rotatable draw-oil ware rollershaft, a needle bar shaft, a pattern chain, and a main cam shaft: a wormgearing consisting of a worm wheel fixed on said shaft, and a rotatablelongitudinally movable worm enmeshed with said worm wheel; a compressionspring operatively associated with the worm and disposed to normally actfor moving the same in one rectilinear direction for imparting arotating movement to the draw-off shaft through the worm wheel; meansactuated by the needle bar shaft and operable for rotating the wormformovement in the opposite rectilinear direction in relation to the wormwheel and against the action of said spring to compress the same for itsaction on said worm; means governed by the pattern chain for controllingthe action of said spring on the worm; and means controlled by the maincam shaft for relieving said worm from the action of said spring.

8. In a knitting machine, a take-up element and a combined draw-offtensioning and releasing device for saidelement, said device including aspring compressible to various degrees to impart movement to saidelement under various degrees of tension.

9. In combination with the ware roller shaft and main cam shaft of aknitting machine, a combined draw-off tensioning and releasing devicefor said ware roller shaft controlled by said main cam shaft, saiddevice including a spring compressible to various degrees to impartmovement to said element under various degrees of tension.

10. In a flat knitting machine having a drawofl shaft: spring meansassociated with said shaft and deformable to apply tensioning drivingforce to the latter; and means operable to regulate the deformation ofsaid spring means for varying the tensioning driving force appliedthereby to said shaft.

11. In a flat knitting machine having a drawofl shaft: a yieldableelement associated with said shaft and deformable to apply tensioningdriving force to the latter; and means operable to regulate thedeformation of said yieldable element for varying the tensioning drivingforce applied thereby to said shaft.

12. In a flat knitting machine having a drawofi shaft: a springassociated with said shaft and compressible for applying a tensioningforce to the latter; and means operable to regulate the compression ofsaid spring for varying the tensioning force applied thereby to saidshaft.

13. In a flat knitting machine having a drawoff shaft: a springassociated with said shaft and compressible for applying a tensioningforce to the latter; means operable to regulate the compression of saidspring for varying the tensioning force applied thereby to said shaft;and means operable for automatically controlling said compressionregulating means.

14. In a knitting machine, the combination with a fabric take-up elementof: a spring compressible for applying a rotating tensioning force ofpredetermined degree to said element; and means operable to regulate thedegree of compression in said spring for selectively increasing anddecreasing the degree of tensioning force to be applied by said springat various times during knitting.

15. In a knitting machine, the combination with a fabric take-up elementof a spring compressible for applying a rotating tensioning force ofpredetermined degree to said element; means operable to regulate thedegree of compression in said spring for selectively increasing anddecreasing the degree of tensioning force to be applied by said springat various times during knitting; and means operable for automaticallycontrolling said compression regulating means.

16. A fabric take-up device for knitting machines coniprising: a fabrictake-up shaft rotatably supported on said machine; a stub shaft;

a bracket supporting the stub shaft for rotating versely of the fabrictake-up shaft; a spring associated with said bracket and stub shaftdisposed to be tensioned by rotation of said stub shaft and untensionedfor' sliding said stub shaft; and a gearing between said shafts operableto cause the tensioning of said spring by rotation of the stub shaft inrelation to the fabric take-up shaft, and to cause the rotation of saidtake-up shaft through the sliding motion of the stub shaft byuntensioning of the spring.

17. A fabric take-up device for knitting machines comprising: a fabrictake-up shaft rotatably supported on said machine; a stub shaft; aslidable bracket supporting the stub shaft for rotating motionlongitudinally and sliding motion transversely of the fabric take-upshaft; a spring associated with said bracket and stub shaft disposed tobe tensioned by rotation of said stub shaft and untensioned for slidingsaid stub shaft; a gearing between said shafts operable to cause thetensioning of said spring by rotation of the stub shaft in relation tothe fabric take-up shaft, and to cause the rotation of said take-upshaft through the sliding motion of the stub shaft by untensioning ofthe spring; and means for sliding said bracket in relation to saidshafts to untension said spring without affecting said gearing.

18. In a flat knitting machine having a drawoif roller: a mechanism forapplying a prederegulate the degree of compression in said spring forautomatically fractionally increasing and decreasing the tension forceapplied by said mechanism in timed relation to the knitting.

19. In a fiat knitting machine having a drawoff roller: a mechanism forapplying a predetermined rotative tension force to the draw-off roller,said mechanism including a compression spring; means automaticallyoperable to regulate the degree of compression in said spring forautomatically fractionally increasing and decreasing the tension forceapplied by said mechanism to a predetermined amount; and means forcompletely neutralizing the rotative eflect of said rotative tensionforce on said roller, all of said alterations in tension forcesbeingeffected at predetermined times in relation to the v knitting.

20. In a flat knitting machine having a drawofi roller: a mechanism forapplying a predetermined rotative tension force to the drawofi roller,said mechanism including a compression spring; means automaticallyoperable to regulate the degree of compression in said spring forautomatically fractionally increasing and decreasing the tension forceapplied by said mechanism to a predetermined amount; and means forautomatically controlling said compression regulating means in timedrelation to automatically controlling said compression regulating meansin timed relation to the knitting.

22. In a fiat knitting machine having a drawoif roller, a pattern chain,and a main cam shaft: a mechanism for applying a predetermined rotativetension force to the draw-oil roller, said mechanism including acompression spring; means controlled by the pattern chain in timedrelation to the knitting and operable to regulate the degree ofcompression in said spring for automatically increasing and decreasingthe rotative force applied by said mechanism to a predetermined amount;and means governed by the main cam shaft for completely neutralizing therotative efiect of said rotative tension force on said roller.

23.In a full-fashioned stocking fabric knitting machine, a stockingfabric take-up device, a. coilspring operativel'y associated with saiddevice and compressible Ito apply a tensioning force to the latter, andmeans for automatically controlling the degree of compression of thespring for varying the te'nsloning force applied thereby to said deviceat predetermined points in the knitting of the stocking fabric.

ALFRED HOFMANN. DONALD G. TRUTNER.

